Cancer, Carcinogens, Obesity: How Harmful is Diet Soda?

As if you needed more things to worry about with regard to your health, diet soda is rising up the ranks of most polarizing things we put in our body.  We’ll look at the impact of both artificial sweeteners and the often overlooked artificial colors found in diet drinks.

Artificial sweeteners are used as a substitute for sugar by individuals looking to lose weight or maintain a healthy body weight.  Saccharin, aspartame, and sucralose are three of the most popular artificial sweeteners used in diet sodas, diet teas, and workout supplements.  A typical can of soda contains about 40 grams of sugar, which would lead some to believe that a can of diet soda contains 40 grams of artificial sweeteners.  This is not the case since artificial sweeteners are much stronger than sugar.  Aspartame is 200x sweeter, saccharin is 300-500x sweeter, and sucralose is 600x sweeter.  Therefore, there is only a fraction of these substances found in diet products compared the sugar in regular drinks.

Many people will cite research that states artificial sweeteners cause cancer and should be avoided at all costs.  While some animal studies suggest this, it’s important to look at the limitations and biases of these studies.  First is the dose.  In the studies that link artificial sweetener consumption to cancer, the mice are given obscene amounts of sucralose.  I’ve seen anywhere from 60-3,000 mg/kg of bodyweight.

Let’s look at the low end of the spectrum, 60mg/kg of bodyweight.  I’m about 85kg, so the equivalent for me would be 5,100mg of sucralose.  What does this look like in terms of volume?  Oh, only about 425 packets of Splenda.

You may be thinking, how could 425 packets of Splenda equate to only 5.1g of sucralose?  Remember how much sweeter artificial sweeteners are compared to sugar.  When you look at a packet of Splenda, only a fraction of the contents are sucralose itself.  The rest are fillers like dextrose to give the packet some bulk.  Think about it, since sucralose is so sweet, you would literally only need a few pellets to sweeten your coffee.  But these companies have to put something in there or else consumers would think the packets are completely empty.

What about obesity?  There are multiple studies linking artificial sweetener consumption to obesity.  Again, it’s crucial to look at the limitations of correlative research.  Correlation does not equal causation.  Correlation can be helpful in identifying trends, but it’s important to realize that trends do not automatically equal cause and effect.  If a high number of obese individuals drink diet soda, it does not necessarily mean that diet soda causes obesity.  In my opinion, the far more likely takeaway is that these obese individuals are looking for a calorie-free beverage to help themselves lose weight.

Despite being calorie free, some people believe that diet soda causes an insulin spike.  Spikes in insulin temporarily limit fat oxidation (fat burning).  Insulin is a storage hormone released by the pancreas in response to the consumption of food, carbohydrates in particular.  It helps to remove sugar from the bloodstream and transport it to muscle or adipose tissue (a very simplified explanation but all you really need to know for the purpose of this article).

Think logically for a moment.  If you drank a diet soda, and it caused an insulin spike, you would go hypoglycemic and pass out every time.  Your insulin would elevate, and since there are no sugars entering the bloodstream (because diet soda is calorie free), the insulin would lower your fasting blood glucose to a dangerously low level.  Obviously, this is not the case when you’re drinking a diet coke or a sugar free rockstar energy drink.  Thus, any potential elevation of insulin from artificial sweeteners would be so insignificant that it would make virtually no difference in terms of fat storage.

What about cravings?  Some suggest that the sweet taste of diet soda would trigger a signal in the brain to crave food.  I’ve read about the role of excitotoxins found in artificial sweeteners and their impact on the brain but it feels like a bit of a reach.  I’m not saying it isn’t possible, but at best the jury is still out on this one.  Cravings and hunger pangs are generally caused by blood sugar responses.  Since diet soda has little to no impact on blood sugar, it should not be an issue.

It appears that sucralose in particular can have an impact on gut health.  Whether it’s good or bad is unknown.  The funny thing about gut health is that we know so little about it, all we know is that it’s important.  It will likely take another 10-20 years before we have any definitive research on how to optimize our gut bacteria via diet, lifestyle, etc.

What is often overlooked is the potential health impact of artificial colors.  When different diet soda flavors are manufactured, they don’t magically come out brown or red or orange.  Artificial colors are added to the formula for visual effect.  Seven artificial food dyes remain on the FDA’s approved for consumption list.  Whether or not the FDA truly has your health interests in mind is certainly up for debate, but this is the only standard we have at the moment.  Throughout history, numerous dyes have been taken off the FDA’s approved list due to links with cancer, migraines, and even anxiety.  It is not as if the approved list isn’t a dynamic one.

A study in rats showed memory and learning impairments, but only at a high dose.  And when I say high, I mean really high.  In this study, the rats were given 70mg/kg of an artificial food dye.  The equivalent for myself would be 5,950mg.  If you’re curious, this equates to 228 bottles of Gatorade or 88 bottles of Orange Crush.  Good luck drinking that in one sitting.

An interesting tidbit on that study is that Taurine served as a neuroprotectant for the rats.  Taurine is an amino acid found in many workout supplements.

What about a more reasonable dose?  In that same study, there was a group of rats given 7mg/kg of artificial colorings.  This would equate to 595mg for me, or about 9 bottles of Orange Crush.  Still high, but at least it’s a somewhat reasonable dose in a 24 hour period.  The mice in this group showed a reduction in glial cells.  Glial cells are found in the central nervous system.  They provide support and protection for neurons.

Caramel color is the most widely known and consumed artificial color.  The issue with caramel color is that it can lead to the formation 4-methylimidazole (4-MEI) during the manufacturing process.  4-MEI is a carcinogen that can have adverse effects on health.  The mean concentration of 4-MEI in beverages varies wildly.  Coca Cola contains about 11ug/L while Goya Malta, a non-alcoholic beer, contains about 1,000ug/L.

A recent study determined that caramel colors are not genotoxic or carcinogenic and that normal consumption did not pose any undue health risks.  However, the study was funded by the International Technical Caramel Association (who knew that was a thing).  The study stated that the majority of the artificial coloring was excreted through feces.  Some people who have consumed artificially colored workout supplements can attest to this.  When I worked in the supplement industry, I recall numerous instances where customers would call and wonder why their toilet was blue or purple.

Unlike artificial sweeteners, artificial colors serve no purpose.  It’s simply vanity.  I would have no issue with someone who chooses to avoid them.  Even if the risk is dose dependent, naturally colored drinks and supplements are becoming more ubiquitous.  Hell, you could even choose a clear drink like Sprite to avoid food dye consumption.

How you structure your diet is your prerogative.  My issue is with the loudmouth fear mongering that occurs with health “experts.”  We have this obsession with looking at foods and ingredients in isolation rather than the whole picture.  You have to look at everything in context.  The body is a dynamic organism that constantly changes given the environment in an attempt to maintain homeostasis.  My advice?  Use diet drinks as a tool to help maintain a healthy body weight.  If you’re in the mood for something sweet, grab a diet coke instead of a 500 calorie caramel macchiato.

If you were expecting me to provide evidence that diet soda is going to kill you in one way or another, I’m sorry for disappointing you.  I’ll never be a famous health enthusiast because I don’t make ridiculous claims.  Call me crazy but I enjoy the truth, and the truth is often quite boring.